【作者】 罗云菊；

【导师】 刘东燕；

【作者基本信息】 重庆大学 ， 岩土工程， 2008， 博士

【摘要】 西部大开发,经济和城市化迅速发展,大量人口涌入城市,垃圾巨增,需建新的垃圾卫生填埋场处置垃圾,但西部山城经济条件滞后,技术力量薄弱,卫生填埋场也难以达到100%的垃圾无害化处置,污染问题仍然存在。同时,由于城市化水平提高,上世纪80年代前修建的位于城市郊区的非卫生填埋场(简易垃圾填埋场),已迫近城市中心区,且由于无卫生防护措施对周边环境产生严重污染,已不适应现代需要,必须进行封场整治。因而垃圾卫生填埋场的建设和简易垃圾填埋场的封场整治均存在污染控制问题,而污染控制的关键是要掌握渗滤液和填埋气的运移规律。故卫生填埋场的建设和非卫生填埋场的封场整治,均要进行渗滤液、填埋气运移规律及其污染控制研究。但西部山城垃圾中易降解的有机物含量高,填埋场地形地貌为山地,地表切割深,沟谷发育,地质条件复杂,褶皱构造和断层裂隙较为发育,岩性多样,存在强烈的非均质和各向异性,与沿海平原发达城市垃圾填埋场的垃圾特性和地质条件差异极大,平原沿海发达城市的研究结论不能直接应用于山城。因此西部山城垃圾填埋场气液运移规律及其污染控制研究成为目前急待解决的重要问题。本文通过现场调研,理论分析,室内试验,现场实测及数值模拟等多种手段,对此问题进行了系统的研究。论文首先分析了西部山城垃圾特性及其填埋场地质环境,计算渗滤液和填埋气的产生量;在此基础上,采用孔隙——裂隙双重介质理论、溶质弥散理论,概化西部山城垃圾填埋场渗滤液渗流物理模型,之后由地下水渗流和溶质运移耦合,建立西部山城垃圾填埋场渗滤液渗流污染数学模型,并通过渗滤液COD浓度、地下水水位的模拟值与实测值对比,校正识别模型,最后得到符合客观实际的数学模型。以典型的西部山城简易垃圾填埋场一为代表,采用校正后符合客观实际的数学模型,模拟分析西部山城垃圾填埋场,场内外渗滤液渗流污染特性。此典型西部山城垃圾填埋场内有三条断层通过,断层部位岩体裂隙发育。数值模拟研究中,对此实际垃圾填埋场、断层通过部位进行防渗整治后的填埋场,两种工况,从渗滤液COD浓度随时间的变化规律、渗滤液运移方向的变化规律、以及渗滤液浓度扩散变化规律三个方面,分析对比其渗滤液渗流污染特性,由此可得到西部山城垃圾填埋场渗滤液渗流运移规律。断层或裂隙通过部位,渗滤液渗流形成了一个强径流带,改变了渗滤液渗流路径。场内,治理前的垃圾填埋场,其断层通过部位渗滤液COD浓度值高于治理后填埋场的同一部位COD浓度值约800 mg/L;场外,治理前垃圾填埋场外50m范围内,断层附近监测井渗滤液COD浓度值高于治理后填埋场的同一部位监测井COD浓度值约200 mg/L。断层未治理前填埋场渗液COD浓度最大值位于填埋场中部三条断层的交汇处,治理后渗滤液最大浓度值出现在填埋场的南端,地表标高较低的部位。在建立西部山城垃圾填埋场渗滤液渗流污染模型,进行渗滤液渗流污染规律研究的同时,采用连续介质力学、气体动力学理论,建立西部山城垃圾填埋场填埋气在场内外迁移的数学模型,通过对模型求解,MTLB平台编程,计算分析填埋场填埋气的迁移状况,并与实测结果进行对比,结果表明所建的模型是符合客观实际的,理论计算和实测综合分析,得到的西部山城垃圾填埋场填埋气迁移扩散规律的结论,能为填埋气污染控制提供科学依据。西部山城垃圾填埋场填埋气迁移范围在25m范围内,断层通过部位迁移量大,沿断层通过部位50m后仍有填埋气迁移的现象。填埋场内,随着垃圾体埋深增加,填埋气纵向的迁移量越来越小;填埋场中导气井埋深设置在垃圾体埋深的一半范围内最佳。根据西部山城垃圾填埋场渗滤液、填埋气迁移渗流规律,提出相应的填埋场环境污染控制措施,并对控制措施进行研究,得到最佳的控制方案。更多还原

【Abstract】 With the development of western mountain city of development, and population expand rapidly; the waste quantity increase enormously. These cities need to build a lot of sanitary landfills to disposition garbage. But, due to the economy and science and technology are less dexeloment, there is pollution in the same sanitary landfill. At the same time, there are many simple rubbish dumpings and burials (simple landfills) which built in 80’s last century in western mountain city, and these simple rubbish dumpings and burials are serious pollution in environment, and they had didn’t adapt current needs. The simple landfill must be close up and renovate. The simple landfill and the sanitary landfill are pollution in environment. Therefore, not only building landfill but also renovating simple landfill, the control pollution must be research. But the pollution is come from the leachate and gas movement. In order of the western mountain city enxironment is beatuful, the leachate and gas movement law and the pollution control must be to research.The studies on landfill pollution control of plain cities are under way, but so far, there is practically no report of studies on that of mountain cities. The research conclusion of plain cities landfills cannot be applied to mountain cities, since landfills of plain and mountain cities differ in topographic and geological conditions, the topography of mountain cities landfills being mostly valley and lithology of stratum in mountain cities being complicated with cranny. Therefore the western mountain city landfill’s gas and liquid luck changing law and their contamination control studying is an important urgently problem. In this paper, the author adopts survey and measurement by the scene, theoretical analysis, interior testing and numerical simulation method to study this problem.First, the author analyses the western mountain city garbage and landfill characteristic property, calculate leachate and landfill gas quantity, on this basis, generalize the physics model of leachate seepage, through adjust boundary and parameter reasonably, generalize the fault and rock crack media of the landfill to a porous medium. Then build western landfill mathematic model of leachate seepage, and contrast the values between the density of the leachate、groundwater level which gained by numerical simulation and measured value, then revise this model, and obtain the reasonably mathematical model of leachat movement in mountain city of west china, at same time, the results show that adjust parameters reasonably, it is feasible to adopt porous medium simulate crack medium.Finally, adopt distinguished mathematic model to simulate and analyze leachate seepage and pollution regular pattern of real landfill which the fault had not been renovated, and the remediation landfill which the fault had been renovated. Result indicates that leachate forming a stronger transfusion pollution zone in fault crack, breaks have changed leachate seepage route in structure. In the landfill and on the side of landfill, the COD concentration in the actual landfill which the fault had been not renovated is 800 mg/L and on the side of actual landfill is 2 00 mg/L higher than the landfill with no fault which the fault had been renovated. The leachate concentration in the near the center of landfill is maximal in the real landfill which the fault had not been renovated, but the leachate concentration in south of landfill which the the fault had been renovated.While building western mountain city model and researching on the law of leachate seepage and pollution, establish landfill gas migration model in landfill and outside landfill, solve this model and analyze the situation of landfill gas movement, then contrast the results between simulated value and real measure value, the result is close, explains that the model is accord with objective reality, the gas migration conclusion can provide scientific basis for landfill gas contamination control. The landfill gas movement length is less than or equal to 25 m in the landfill where there is not fault, the length is equal or more than 50 m in landfill where there is fault.By combined reality measures with numerical value simulates method, gets the western mountain city seepage law of landfill leachate and gas, brings forward corresponding landfill environmental pollution measurement, and carries out analysis on controlling the contaminating scheme according to this gas-liquid seepage law. To control leachate and landfill gas penetrate to outside in the fracture structure passing location in western mountain city landfill, we can adopt the method of active periphery exhaust ties with the grout curtain.更多还原